import matplotlib.pyplot as plt
plt.rcParams['font.sans-serif'] = 'SimHei'
rate = [1,5,3,8]
labels = ['一月','二月','三月','四月']
plt.figure(figsize=(6,9))
explode = (0.1,0,0,0.05)
patches, ltext, ptext = plt.pie(rate, explode=explode, labels=labels,autopct='%.1f%%', shadow=False, startangle=90)
for x in ltext:
    x.set_size(20)
for x in ptext:
    x.set_size(24)
plt.axis('equal')
plt.legend()
plt.show()